Jump to content

Just blew an AR-3A Woofer


taynos

Recommended Posts

1 hour ago, DavidDru said:

Jkent is correct.  The guy in Chicago had better know what surrounds to use.  There are many out there but only a few sources will provide the correct ones.  With the masonite ring these are difficult to get aligned in terms of height, thus the shimming is easiest becuse shims help hold the cone up at the proper height to glue.

Here is a better photo of what mine on my nines look liked as I was doing the surrounds.

 

This is what he said earlier today after I brought up the Masonite Ring.

"I'm aware that it may have been there before they were worked on at one time, so if I need to shim up the foam ring at the edge, I can use half of a one piece gasket to bring the edge up."

He has been a speaker and tube amp tech for several decades. He came very well referred by a friend, after meeting him I have full confidence he knows what he's doing. I am very thankful for the members of this forum for making sure I dot my I's and cross my T's throughout the process.

Thanks to everyone.

Link to comment
Share on other sites

11 minutes ago, RoyC said:

I'm not aware of any source for the masonite ring. If the voice coil is being replaced, the spider position can be adjusted somewhat to compensate for the missing ring. Hopefully the OP's speaker repair person will save the original cone. There is a re-coning kit available, but the new cone is much lighter and stiffer than the original...and it does not sound the same.

Interestingly, the first foam surround/ferrite magnet version of the AR 12 inch woofer (1970) did not have the masonite ring under the surround. I haven't seen many, but I have re-foamed enough of them to know this was the case. It can be identified by the foam damping ring on the cone, which was retained from its cloth surround predecessor. This "transitional" woofer was short-lived. By 1971, the woofer had the masonite ring and had lost the damping foam ring on the cone.

Roy

Thanks Roy. I had read a forum post of yours a while back where you brought up the difference in the orginal cone vs the new cone in the re-coning kit. I do believe we are going with the new cones that are lighter and stiffer so I will lose the authenticity of the OEM unfortunately.

When I get the cabinets back I can take a look at the serials to see if they are pre-1970 and possibly did not ship with the masonite ring under the surround...

Finally, in terms of not having a source for a masonite ring supplier, would something like one of these 12" speaker gaskets do the trick? 

http://www.speakerworks.com/speaker_gaskets_s/71.htm

 

Link to comment
Share on other sites

3 minutes ago, taynos said:

Finally, in terms of not having a source for a masonite ring supplier, would something like one of these 12" speaker gaskets do the trick? 

http://www.speakerworks.com/speaker_gaskets_s/71.htm

 

Probably not....The AR woofer basket is a unique size. Those gaskets are also typically much thicker than the masonite ring.

Link to comment
Share on other sites

6 hours ago, RoyC said:

Probably not....The AR woofer basket is a unique size. Those gaskets are also typically much thicker than the masonite ring.

yeah, the masonite ring is 1/8" thick, the OD matches the OD of the foam, and the ID matches the OD of the roll.....they should be ~10 3/8" OD, and about 9 3/4 to 9 7/8" ID IIRC.  like I said, you can make them pretty easy on a scroll saw, with a jig consisting of a board with 2 holes offset 1/4" to 5/16" clamped to the scroll saw's table so the further hole is 5 3/16" from the blade.  take your masonite blank, drill a hole 5 3/16" from the edge the size of the dowel, place it over the dowel, turn on the saw, and spin the blank to get the OD....drill a hole inboard about 1/4" from the edge in your blank, put the saw blade through it, move the dowel to the closer hole and repeat....

or find a prototype shop with a waterjet or laser cutter in your area, and they can cut the rings out of masonite or plastic (HDPE, polypro, ABS, etc).....

Link to comment
Share on other sites

8 hours ago, taynos said:

When I get the cabinets back I can take a look at the serials to see if they are pre-1970 and possibly did not ship with the masonite ring under the surround...

taynos,

The serial number would be of no help in this case. These woofers are rare and have only been found in some 3a's manufactured in 1970. They are identified by a damping ring around the dust cap (like the cloth surround woofer). If your woofer cones do not have the damping ring, they most likely had the masonite surround ring.

Roy

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...